Auto pilot principle, control or setting, SOLAS requirement
Auto pilot principle
Autopilot has a knob to set course.
Autopilot also receives gyro feedback from gyro.
The difference between the set course and gyro feedback will be compared by the comparator.
Comparator will generate an error signal.
Comparator will send this error signal to master solenoid.
Master selonoid will operate hydraulic telemotor.
Now, The heading will come to the set course and error will be zero.
Finally comparator will send this zero error signal to master solenoid for closing the system.
Autopilot control or setting
Course selector: set course
Off course: limit of course deviation. Give Alarm.
Rudder rate: rudder response rate. If too fast – overshoot, if too slow – steering sluggish.
Rudder limit: rudder angle limit. If too large angle – overshoot, if too small angle – steering sluggish.
Counter rudder: corrective rudder angle after vessel coming to the set course. If too low setting – overshoot, if too high setting – delay.
Weather/ Yawing: low valve in good weather – tight steering, high value in bad weather – good adjustment.
FU/NFU: rudder command using wheel and rudder command using tiller.
Components of auto pilot
Four components: comparator, controller, feedback, actuator.
Comparator: The difference between the set course and gyro feedback will be compared by the comparator.
Controller: 3 type – proportional, derivative, integral control.
Feedback: Autopilot receives gyro feedback from gyro. comparator gets rudder feedback from rudder angle.
Actuator: hydraulic motor which move the rudder.
SOLAS CH V / Regulation 19
Heading Control or Track Control systems to be fitted to all vessels of 10000 GT and upward.